WED 13 APR 2016: A SLIGHT chance of thunderstorms:
Similar setup on Wednesday to Tuesday, with a large W-E elongated upper trough sitting across eastern Atlantic and British Isles. The associated cold mid-levels combined with diurnal heating will generate 300-500J/kg CAPE (locally higher in Ireland). Forecast profiles are quite dry, and convective initiation will be heavily reliant on low-level wind convergence (from sea breeze and topographical effects), hence even within the broad SLGT there will be a good deal of dry weather still in many places with showers generally well-scattered and focussed over small areas - particularly near or just inland from coastal areas.
Scattered showers and a few thunderstorms will develop, particularly from late morning and moreso through the afternoon and into the evening, capable of producing hail locally bigger than 1.5cm in diameter in any stronger cells. DLS is rather weak and hence showers/storms will generally be rather lacking in organisation, but slow storm motion will likely produce 10-15mm rain accumulations in just 1-2 hours, with elements of shower training also - and hence there is a risk of some local surface water flooding issues.
It is hard to ascertain any particular areas where showers/storms are most likely to occur, hence the broad SLGT, although most NWP are at least in agreement for north Devon and parts of East Anglia, along with Kent/Sussex and SE Wales. Coverage of showers/storms will gradually decrease through the evening hours as nocturnal cooling takes over. A few funnel clouds or a weak tornado are possible close to convergence zones.